I logged in using my LinkedIn account and it logged me into a different user’s account. There’s not much direction in where to report bugs (also I couldn’t find where/how to logout) so I hope posting this here will get some attention from the developers.
Bugs should always be reported as GitHub Issues. Whenever reporting a bug, please check first that there isn’t already an issue for it and provide as much detail as possible.
FCC does not support logging in with any method besides email. You should not be able to log in with a LinkedIn account at all.